Editing Postcodes in the United Kingdom (section)

===Earlier postal districts===
====London====
{{main|London postal district}}
The London post town covers 40% of [[Greater London]]. On inception (in 1857/8), it was divided into ten postal districts: EC (East Central), WC (West Central), N, NE, E, SE, S, SW, W, and NW. The S and NE sectors were later abolished. In 1917, as a wartime measure to improve efficiency, each postal district was subdivided into sub-districts each identified by a number; the area served directly by the district head office was allocated the number 1; the other numbers were allocated alphabetically by delivery office, e.g. N2 East Finchley delivery office, N3 Finchley delivery office, N4 Finsbury Park delivery office etc. Since then these sub-districts have changed little.

Some older road signs in Hackney still show the North East (NE) sector/district.

====Other large cities and towns====
[[Image:BirdbrookRoadSigns.jpg|thumb|right| Street name signs on Birdbrook Road, Great Barr, Birmingham, showing old "Birmingham 22" postal district (top) and modern "B44" postcode.]]
Following the successful introduction of postal districts in London, the system was extended to other large towns and cities. Liverpool was divided into Eastern, Northern, Southern and Western districts in 1864/65, and Manchester and Salford into eight numbered districts in 1867/68.<ref name=bpma/>

In 1917, [[Dublin]]—then still part of the United Kingdom—was divided into [[List of Dublin postal districts|numbered postal districts]]. These continue in use in a modified form by [[An Post]], the postal service of the [[Republic of Ireland]]. In 1923, Glasgow was divided in a similar way to London, with numbered districts preceded by a letter denoting the compass point (C, W, NW, N, E, S, SW, SE).<ref name=bpma/>

In January 1932 the Postmaster General approved the designation of some predominantly urban areas into numbered districts.<ref name=bpma/> In November 1934 the Post Office announced the introduction of numbered districts (short postal codes) in "every provincial town in the United Kingdom large enough to justify it". Pamphlets were issued to each householder and business in ten areas notifying them of the number of the district in which their premises lay. The pamphlets included a map of the districts, and copies were made available at local head post offices. The public were "particularly invited" to include the district number in the address at the head of letters.<ref name=times1934>{{Cite news|title=Numbered P.O. Districts in Country Towns. Aid To Accurate Delivery |work=[[The Times]] |page=14 |date=20 November 1934 }}</ref>

A publicity campaign in the following year encouraged the use of the district numbers. The slogan for the campaign was "For speed and certainty always use a postal district number on your letters and notepaper". A poster was fixed to every pillar box in the affected areas bearing the number of the district and appealing for the public's co-operation. Every post office in the numbered district was also to display this information. Printers of Christmas cards and stationery were requested to always include district numbers in addresses, and [[election agent]]s for candidates in the upcoming [[1935 United Kingdom general election|general election]] were asked to ensure they correctly addressed the 100&nbsp;million items of mail they were expected to post. Businesses were issued with a free booklet containing maps and listings of the correct district number for every street in the ten areas.<ref name=times1935>{{Cite news|title=Postal District Numbers Appeal For Use in Addresses|work=[[The Times]] |page=14 |date=29 October 1935}}</ref>

The ten areas were:<ref name=times1935/>
*[[Birmingham]]
*[[Brighton]]/[[Hove]]
*[[Bristol]]
*[[Edinburgh]]
*[[Glasgow]]
*[[Leeds]]/[[Bradford]]
*[[Liverpool]]
*[[Manchester]]/[[Salford, Greater Manchester|Salford]]
*[[Newcastle upon Tyne]]
*[[Sheffield]]

For example, [[Toxteth]] was ''Liverpool 8''. A single numbering sequence was shared by Manchester and Salford: letters would be addressed to Manchester 1 or Salford 7 (lowest digits, respectively). Some Birmingham codes were sub-divided with a letter, such as ''Great Barr, Birmingham 22'' or ''Birmingham 22a'',<ref name=Will>{{Cite web |url=http://www.jacomb.com/w1951_1960.htm |archive-url=https://web.archive.org/web/20070208065042/http://www.jacomb.com/w1951_1960.htm |url-status=dead |archive-date=8 February 2007 |title=1951 will, using address in "Birmingham 22a" |publisher=Jacomb.com |access-date=1 September 2010 }}</ref> as can still be seen on many older street-name signs.